Mining environments, particularly open pit surface mining environments, present unique challenges to maintaining safe operation of vehicles. The workhorse of a modern surface mine is a mine haul truck, which is a dump truck capable of hauling up to four hundred, and in some cases over four hundred, tons of material. Haul trucks are some of the largest land vehicles ever built. As such, they are characterized by limited maneuverability, relatively slow acceleration and deceleration, and poor sight lines on every side of the vehicle. In particular, the rear and side opposite to the operator's cabin of a mine-haul truck present enormous blind spots for the haul truck operator.
Within a mining environment there may be many other vehicles such as shovels, dozers, bucket wheel excavators, or other equipment that are each similarly difficult to control. Because the vehicles are so large, they can have large blind spots, large turning radii, and slow braking capabilities, making navigating the vehicles to a given destination extremely difficult. In many cases, though, by accurately positioning these vehicles in proximity to other vehicles or geographical features of the mine, the mine's efficiency can be greatly improved. Additionally, through accurate navigation, dangers of injury or property damage resulting from a collision can be mitigated.
In one example of conventional pit mining operations, material is blasted from a face, picked up by a shovel, and loaded into the bed of a haul truck. The haul truck then moves the material to a crusher for processing. Shovels can be several times larger than a haul truck. A typical electric shovel can measure 100 feet in length from the rear of the crawler portion to the end of the bucket. The overall height of the shovel can measure 70 feet with a typical bucket height of 45 feet. A typical distance from the center of rotation of a shovel to the distal end of the bucket is 80 feet.
Haul truck loading tends to be a rate limiting operation in the material extraction process of a mine. Conventionally, a haul truck will back up along a path that is perpendicular to a face to a position on one side of the shovel. Once the truck is in position beside the shovel, the shovel operator will retrieve material from the face and load the truck. Once loaded, the truck proceeds to a crusher. Given the size and responsiveness of a conventional mine truck, the process of navigating a truck into a desired position can take some time. Additionally, a collision between a mine haul truck and a shovel or other mining equipment can be catastrophic resulting in not only injury or death, but in millions of dollars in equipment damage and downtime. Accordingly, mine-haul truck drivers tend to be tentative when moving their vehicles into position for loading, further reducing the vehicle's efficiency.
Ideally, as a first truck is being loaded on a first side of a shovel, a second truck will move into position on the other side. This maximizes the use of the shovel, allowing it to be continuously engaged in the loading operation, rather than waiting for the next truck to move into position.
FIG. 1 shows a conventional solution for assisting a mine-haul truck to navigate into a loading area besides a shovel. In the arrangement of FIG. 1, power shovel 105 is working at a mine face 102. Power shovel 105 includes lower assembly 110. Lower assembly 110 includes first and second crawler tread 115a, and 115b. Power shovel 105 includes an upper assembly 120, which is rotationally coupled to lower assembly 110 via a rotational bearing 125. Upper assembly 120 includes boom 127. Attached to boom 127 at a hinge is a handle 130. At a distal end of handle 130 is a bucket 135. Upper assembly 120 also includes a cab 140 in which an operator of power shovel 105 resides. In the example operation shown in FIG. 1, power shovel 105 is electrically powered via dragline tether 145 which provides electrical energy to shovel 105. Other shovels, such as hydraulic shovels, may not be powered via a dragline tether or power cable and instead can operate independently. In either case, the upper assembly of a shovel often presents a large structure extending rearwards away from the shovel's cab. As the shovel rotates, both the boom and rear portion of the upper assembly can pose a hazard to nearby objects as it rotates about the shovel's rotational bearing. Because the shovel and upper assembly must enclose additional power generation machinery, the upper assembly of a hydraulic digger that does not rely on a dragline for power generally extends further in a rearward direction from the shovel's cab.
The conventional arrangement of FIG. 1 shows a first mine haul truck 150 in position to receive material from shovel 105. During the loading of first haul truck 150, however, shovel 105 is rotating back and forth between the first loading position and the face 102. As such, second haul truck 165, which would otherwise be positioned on the opposite side of power shovel 105 from first haul truck 150, must keep clear of the arc of the tale and corners of the upper assembly 120 while loading is occurring at the first loading position. The dangers inherent in backing a haul truck up to an operating shovel often cause truck operators to delay moving into position until the bucket of the shovel is already positioned over the second loading position. This results in wasteful downtime.
The conventional solution to this problem is to attach a boom 155 ending in a highly visible marker 160 to the tail of the shovel 105. Occasionally, power line markers or traffic cones are used for the highly visible marker 160. Conventionally, the operator of the second truck 165 will use the highly visible marker 160 to align the second truck 165 while the first truck is being loaded. After loading of the first truck 150 is complete, and the shovel rotates the bucket back to the face 102 to pick up more material, the second truck 165 backs into position.
Systems have been developed that track the location of mine haul trucks with respect to potential hazards. For example, co-owned U.S. Patent Application Publication No. 2009/0062971 discloses a GPS based system for defining routes and potential hazards in a mining environment. Co-owned U.S. Pat. No. 6,799,100 discloses a permission system for controlling interaction between autonomous vehicles in a mining environment, U.S. Pat. No. 6,487,500 B2 to Lemelson et al., describes a system that uses GPS systems on vehicles, augmented by more accurate position sensors, to alert a vehicle operator of hazards in the operator's vicinity, including other vehicles. U.S. Pat. No. 7,047,114 B1 to Rogers et al., describes a hazard warning system for marine vessels. The Rogers system takes GPS position and data information from marine vessels and forwards that information to those vessels hazard alerts based on the positions of other vessels as well as fixed and semi-fixed hazards derived from nautical charts.